Here is the story of the whole project. This is from the NASM website that also had interviews with the Horten brothers about their work, It is also on tape, their explanation for not restoring the Horten 229 V3 is that they are waiting for their new facility to be completed, this will all in all take 7 years.
Quote:
In 1943 the all-wing Horten 229 promised spectacular performance and the Luftwaffe (German Air Force) chief, Hermann Gring, allocated half-a-million Reich Marks to the brothers Reimar and Walter Horten to build and fly several prototypes. Numerous technical problems beset this unique design and the only powered example crashed after several test flights but the airplane remains one of the most unusual combat aircraft tested during World War II. (Note to the reader: Horten used roman numerals to identify his designs and he followed the German aircraft industry practice of using 'Versuch,' literally test or experiment, numbers to describe pre-production prototypes built to test and develop a new design into a production airplane. The Horten IX design became the Horten Ho 229 aircraft program after Gring granted the project official status in 1943 and the technical office of the Reichsluftfahrtministerium assigned to it the design number 229. This is also the nomenclature used in official German documents).
The idea for the Horten IX grew first in the mind of Walter Horten when he was serving in the Luftwaffe as a fighter pilot engaged in combat in 1940 during the Battle of Britain. Horten was the technical officer for Jadgeschwader (fighter squadron) 26 stationed in France. The nature of the battle and the tactics employed by the Germans spotlighted the design deficiencies of the Messerschmitt Bf 109, Germany 's most advanced fighter airplane at that time. The Luftwaffe pilots had to fly across the English Channel or the North Sea to fulfill their missions escorting German bombers and attacking British fighters and Horten watched his unit lose many men over hostile territory at the very limit of the airplane's combat radius. Often after just a few minutes flying in combat, the Germans frequently had to turn back to their bases or run out of fuel and this lack of endurance severely limited their effectiveness. The Messerschmitt was also vulnerable because it had just a single engine. One bullet could puncture almost any part of the cooling system and when this happened, the engine could continue to function for only a few minutes before it overheated and seized up. Walter Horten came to believe that the Luftwaffe needed a new fighter designed with performance superior to the Spitfire, Britain's most advanced fighter. The new airplane required sufficient range to fly to England, loiter for a useful length of time and engage in combat, and then return safely to occupied Europe. He understood that only a twin-engine aircraft could give pilots a reasonable chance of returning with substantial battle damage or even the loss of one engine.
Since 1933, and interrupted only by military service, Walter and Reimar had experimented with all-wing aircraft. With Walter's help, Reimar had used his skills as a mathematician and designer to overcome many of the limitations of this exotic configuration. Walter believed that Reimar could design an all-wing fighter with significantly better combat performance than the Spitfire. The new fighter needed a powerful, robust propulsion system to give the airplane great speed but also one that could absorb damage and continue to function. The Nazis had begun developing rocket, pulse-jet, and jet turbine configurations by 1940 and Walter's role as squadron technical officer gave him access to information about these advanced programs. He soon concluded that if his brother could design a fighter propelled by two small and powerful engines and unencumbered by a fuselage or tail, very high performance was possible.
At the end of 1940, Walter shared his thoughts on the all-wing fighter with Reimar who fully agreed with his brother's assessment and immediately set to work on the new fighter. Fiercely independent and lacking the proper intellectual credentials, Reimar worked at some distance from the mainstream German aeronautical community. At the start of his career, he was denied access to wind tunnels due to the cost but also because of his young age and lack of education, so he tested his ideas using models and piloted aircraft. By the time the war began, Reimar actually preferred to develop his ideas by building and testing full-size aircraft. The brothers had already successfully flown more than 20 aircraft by 1941 but the new jet wing would be heavier and faster than any previous Horten design. To minimize the risk of experimenting with such an advanced aircraft, Reimar built and tested several interim designs, each one moderately faster, heavier, or more advanced in some significant way than the one before it.
Reimar built the Horten V b and V c to evaluate the all-wing layout when powered by twin engines driving pusher propellers. He began in 1941 to consider fitting the Dietrich-Argus pulse jet motor to the Horten V but this engine had drawbacks and in the first month of 1942, Walter gave his brother dimensioned drawings and graphs that charted the performance curves of the new Junkers 004 jet turbine engine (this engine is also fitted to these NASM aircraft: Messerschmitt Me 262, Arado Ar 234, and the Heinkel He 162). Later that year, Reimar flew a new design called the Horten VII that was similar to the Horten V but larger and equipped with more powerful reciprocating engines. The Horten VI ultra-high performance sailplane also figured into the preliminary aerodynamic design of the jet flying wing after Reimar tested this aircraft with a special center section.
Walter used his personal connections with important officials to keep the idea of the jet wing alive in the early stages of its development. General Ernst Udet, Chief of Luftwaffe Procurement and Supply and head of the Technical Office was the man who protected this idea and followed this idea for the all-wing fighter for almost a year until Udet took his own life in November 1941. At the beginning of 1943, Walter heard Gring complain that Germany was fielding 17 different types of twin-engine military airplanes with similar, and rather mediocre, performance but parts were not interchangeable between any two designs. He decreed that henceforth he would not approve for production another new twin-engine airplane unless it could carry 1,000 kg (2,210 lb) of bombs to a penetration depth' of 1,000 km (620 miles, penetration depth defined as 1/3 the range ) at a speed of 1,000 km/h (620 mph). Asked to comment, Reimar announced that only a warplane equipped with jet engines had a chance to meet those requirements.
In August Reimar submitted a short summary of an all-wing design that came close to achieving Gring's specifications. He issued the brothers a contract, and then demanded the new aircraft fly in 3 months! Reimar responded that the first Horten IX prototype could fly in six months and Gring accepted this schedule after revealing his desperation to get the new fighter in the air with all possible speed. Reimar believed that he had boosted the Reichsmarschall's confidence in his work after he told him that his all-wing jet bomber was based on data obtained from bona fide flight tests with piloted aircraft.
Official support had now been granted to the first all-wing Horten airplane designed specifically for military applications but the jet bomber that the Horten brothers began to design was much different from the all-wing pure fighter that Walter had envisioned nearly four years earlier as the answer to the Luftwaffe's needs for a long-range interceptor. Hencefourth, the official designation for airplanes based on the Horten IX design changed to Horten Ho 229 suffixed with Versuch' numbers to designate the various prototypes.
Hope this helps
